Electrical transformers have a primary coil which is connectable to an AC source and a secondary coil which is connectable to a load. The alternating current flowing in the primary coil generates a magnetic field which in turn induces current in the secondary coil. The voltage induced in the secondary coil is a function of the relative number of turns between the primary and secondary coils and the presence or absence of magnetizable material between the coils.
Variable transformers typically have a single coil acting both as the primary and secondary coils. In such transformers, the secondary coil is formed by a wiping contact which effectively changes the ratio of primary to secondary coil turns. Thus, by moving the wiper, the output voltage produced by the secondary coil is adjusted.
The present invention relates to a variable transformer which functions without the use of a wiping contact.